APC is a free, open, and robust framework for caching and optimizing PHP intermediate code.

Release notesVersion 3.0.9(stable)

Eliminate rand() call when slam_defense is not set (Rasmus)
Fix for __isset problem (Gopal)
Rewrite allocator from a "best fit" to a "next fit" algorithm (Rasmus)
Added a Cache Full counter so we have an idea how many times the segment has filled up causing an expunge (Rasmus)
Report back the correct number of available bytes in the segment instead of the allocated bytes. (Rasmus)
Add cache busy flag which is set when an expunge is underway (Rasmus)
Add automatic serialization of objects in apc_store() (Marcus)
64-bit .ini flag fix (Rasmus)
Static members fix (Gopal)
sma_cleanup() mem leak fix (Rasmus)
Fix for http://pecl.php.net/bugs/5311 (Rasmus)
Fix autoglobals JIT bug (Gopal)
Fix instance bug (Gopal)
Add a lock cleanup safety net to request shutdown (Rasmus)
Fix apc.slam_defense edge-case bug (Rasmus)
User entry memory usage tracking support (Ilia)
Allow keys used in apc_store/apc_fetch/apc_delete to be binary safe and prevent conflicts between keys that are found at the start of other keys. (Ilia)